The scale on a map is 8cm : 2km. If two cities are 56cm apart on the map, what is the actual distance in km between the two cities?
The scale means that every 8cm on the map corresponds to an actual distance of 2km. A distance of 56cm on the map is the same as 7 $\cdot$ 8cm. The actual distance between the two cities is 7 $\cdot$ 2km, or 14km.